Debate Over Whether EKGs Should Become Standard for Teenagers Before Playing Sports

As a veteran nurse, Rhina Paredes had no idea that her athletic young son might bear a heart defect until he fell dead at the age of 15.

After Eric Paredes's death in 2009, Ms. Paredes teamed up with a cardiologist at her hospital, John Rogers, and started a program in San Diego to offer free electrocardiogram screenings for teenagers. Of the nearly 12,000 teens they've scanned so far, 121 were found to bear potentially fatal cardiac...